JERUSALEM -- Wrapping up his fourth Holy Land trip in three months, Secretary of State John F. Kerry voiced optimism Thursday that his low-profile campaign to relaunch U.S.-brokered peace talks is making headway.

But while the top American diplomat is winning praise for persistence, Israeli and Palestinian officials privately say chances of success remain low and that Kerry’s effort has yielded no tangible results so far.

Kerry, who held separate meetings with Israeli Prime Minister Benjamin Netanyahu and Palestinian Authority President Mahmoud Abbas, said serious work was underway.

“It is our hope that by being methodical, careful, patient -- but detailed and tenacious -- that we can lay out a path ahead that could conceivably surprise people, but certainly exhaust the possibility of peace,” Kerry said.

Privately, though, Israeli officials said Kerry was pursuing mostly well-worn ideas, such as goodwill concessions, that have failed to get traction in the past.

“I don’t think anyone expects a breakthrough right now,’’ said an Israeli government official, who was not authorized to speak publicly about the issue. “The obstacles are too high. It doesn’t seem like he’s managed to move the sides.”

After taking office in February, Kerry renewed American engagement in the Israeli-Palestinian conflict to a level not seen since President Obama’s first two years in office. He said he would spend about three months exploring whether it is possible to restart talks.

Officials say Kerry’s numerous visits, meetings and weekly phone calls with Netanyahu, Abbas and their negotiators represent the most aggressive personal effort by a U.S. secretary of State since Condoleezza Rice attempted to broker a deal in the final months of the Bush administration in 2008.

Yet several of Kerry’s attempts to build early momentum with modest achievements have already stalled, and there are no signs that either side is softening its positions.

Palestinians praised Kerry’s effort, but said U.S. policy remains skewed in favor of Israel.

“I’m hesitant to say we are seeing a miraculous transformation in American policy and its blind strategic alliance with Israel,” said Hanan Ashrawi, a member of the Palestine Liberation Organization executive committee.

“He’s going down the same path we’ve been on,’’ said Danny Dayan, the foreign envoy for Yesha Council, which represents Israeli settlers. “As long as the aim of the process is a two-state formula, it will fail. For 20 years that has been the only game in town and we are not even one inch closer.”